Ultra-wideband circularly polarized millimeter wave antenna based on adjacent coupled feed

In order to improve the performance of 5 G Millimeter wave, a new gap-coupled fed ultra-wideband circularly polarized antenna is proposed. Firstly, by fabricating the top structure of the slot antenna ?a C-shaped patch structure can adjust the surface transverse current as well as the longitudinal current to generate circularly polarized waves; then the feed structure at the bottom layer of the antenna is designed and resonance is generated with the top layer of the antenna to expand bandwidth. From the simulation and the measurement results can know that the -10 dB impedance bandwidth of the antenna is 19.21 GHz-45.50 GHz (81.25%); the 3 dB circularly polarized axial ratio (AR) bandwidth is 20.59 GHz-38.33 GHz (60.2%), with ultra-broadband circular polarization performance. The designed antenna has a simple structure, small size, low profile and wide working bandwidth, which can fully include N257, N258 and N261 bands, and has a good application prospect in 5 G communication.